Process and device for the purification of hard water by base-exchanging bodies



Jan. 31, 1928.

E. M. E. FRECHOU PROCESS AND DEVICE FOR THE PURI FICATION OF HARD WATERBY BASE vEXCHANGING BODIES Filed Sept. 24. 1925 Patented Jan. 31, 1928.

UNITED STATES,

1,657,822 PATENT. can-cs.

. nmanezacn nuenm: FBEGEOU, or rams, amen.

PROCESS AND DEVICE FOR THE PURIFICATION OF HARD WATER BY BASE-EXG HANG-ING BODIES Application fled September 84, 1825, Serial No, 58,421, and.in Trance December 19; 1924.

It is known that hard water may be entirely deprived of its calcium andmagnesium salts, and caused to titrate hydrotimetric by filtrationthrough base exchang- B in bodies such as permutites, zeoliths, etc.

otwithstanding the considerable advantages which water thus purifiedwould present, the use of this process has not been general; this beingdue to 0 base exchan 'ng bodies and to the high consumption 0 sodiumchloride required for their regeneration.

The present invention relates to .a process and to a device for thefiltration of water through these base exchangingl substances, thisprocess greatly reducing t e consumption of salt necessary forregeneration.

' One of the devices. usually employed up to now for the filtration ofwater consists of two filters injwhich is placed the per.-

mutite; one of these filters is in use while the other undergoesregeneration; the rate of flow of the water is controlled in such amanner'that the water, when issuing from the device, titrates 0hydrotimetric. The filters are periodically alternated and the filterwhich has just operated is regenerated by means of sodium chloride. Forreducingthe consumption of salt to a minimum, it is necessary to reusethe salt solution until it has taken up amaximum quantity of calcium andthis result can be obtained only if the permutite itself is com letelysaturated with calcium 85 .salts. But i the permutite is completelysaturated with calcium salts before regeneration it is not possible, fora given quantity 0 soft water output, to. purify all of the .water 3 to0 hydrometric. 40 Various processes and apparatus have al- Girculationindoseries in filters i A. reservoir for partly purified water, with apump 6, acts to take the water from the filter 4 and conveying it backinto the filtersthe high price of the regeneration of t an 8 to 10 percent solution of ready been proposed for reducing the consumption ofsalt, such as those which consists in recovering the partially exhaustedsalt solutions and reusing them during a subsequent regeneration processand in thus progressively decreasing their calcium content at theexpense of salt, others consists in regenerating the permutite in a hotcondition, others consist in working upthe permutite in powder form withwater and in several successive operations.

Butall these processes, if they give satisfactoryresults, arecomplicated. In accordance with thepresent invention, use is made {orthe purification of water and e substances of another means, known initself, but which in its new and special application to the softening ofwater by base exchanging materials, permits utilizin in the bestcondition these materials and file regenerating salted solutions. y

This process consists in purifyingt water ina series of filters placedone a er the other and in which water circulates inseries. In this way,it is possible to subject to re generation only a mass completelysaturated with lime and this is done by regenerating the filterssuccessively and in turn. d

The accompanying drawing illustrates, by way of example anddiagrammatically, a device. for carrying out this process- This devicecomprises a filters -'1--2-3-4 In operation three of these filters arein service for purificationf purposes and the iourth is in course ofreeneration.

The circulation of water is periodically effected in the followingsequence:

1' -2 and 3. In regeneration filter 4. l x

: ::::do 2. ..do 3.

isolate each of the filters, with eader 10 for the successive reand withblow off to successivel a salt water generations of the filters, cocks11;

It is to be understood that the number of filters is not limited to 4;it can be inc or reduced according to requirements.

What I claim as m invention and desire to secure by Letters atent is:

series of four- I In an apparatus for the purification of Water, aseries of tanks adapted to contain base exchange substances, said tanksbeing disposed at different levels with respect to 5 each other, a hardWater main, a soft water main, pipes leading from each of the tanks tothe soft water main, a container adapted to contain partly purifiedwater, a pipe leading from one of said above mentioned tanks to saidcontainer, a pump adapted to pumpJo liquid from said container intoanother of said tanks.

In testimony whereof I have signed my name to this specification.

EMILE MARCEL EUGENE FRECHOU.

